A separatist movement has been accused of several attacks against security installations and government buildings.
Gunmen using dynamite have attacked a police station in southeastern Nigeria, a day after two police officers were killed in another attack in the area, police said.
Sunday’s attacks in the state of Imo were the latest violence in the region where separatist violence is on the rise.
“The gunmen came with dynamite in the early hours of today and bombed part of the station at Oru but the assault was repelled,” state police spokesman Michael Abattam told AFP.
He said four of the attackers were killed.
“Four of the gunmen were neutralised and five IED (improvised explosive devices) were recovered.”
Abattam had said on Saturday that a number of gunmen armed with explosives attacked Umuguma police station outside Owerri, the state capital, leaving two police constables dead.
He said some gunmen also invaded the residence of professor George Obiozor, leader of Igbo cultural union Ohanaeze, and destroyed part of the building with explosives.
Obiozor was not at home at the time of the attack, he said.
“We are on the trail of the attackers with a view to bringing them to justice,” he said.
President Muhammadu Buhari on Sunday condemned the attacks, while pledging to end the lingering violence in the region.
“He extends sympathies to the police authorities over the losses of men and materials, and to Professor Obiozor who he urged to maintain his commitment to the peace and oneness of the Federation against these odds,” Buhari’s office said in a statement.
Southeast Nigeria has seen a surge in violence, with more than 130 police and other security personnel killed by gunmen since last year, according to local media tallies.
Authorities have blamed attacks on either the outlawed Indigenous People of Biafra (IPOB) movement, which is campaigning for a separate state for the ethnic Igbo people, or its armed wing, the Eastern Security Network (ESN).
The group has denied responsibility for the violence.
The government has also been accused of high-handedness and extrajudicial killings by rights groups like Amnesty International.
Separatist movements in Nigeria are particularly sensitive after a 1967 unilateral declaration of an independent Biafra republic by dissident Igbo army officers sparked a 30-month civil war.
More than one million people died, most of them Igbos, from the impact of conflict, hunger and disease.